Conditions which adversely affect the production of oil from a well include: (1) the deposition of plugging materials brought out during production (e.g., formation of "scale"); and (2) corrosion of the well tubing and operating equipment in the well. Treatment of a well by introducing an oil field chemical can increase the rate of production, prolong the producing life, and lessen the deterioration of well equipment.
However, it is difficult to treat the individual wells which are widely dispersed geographically, which are inaccessible during operation, and which contain fluids of widely varying composition.
One moderately successful approach is disclosed in U.S. Pat. No. 3,676,363, Mosier, issued Jul. 11, 1972, said patent being incorporated herein by reference. The capsules disclosed therein are weighted. The capsules are deposited in the sump of a well where they slowly dissolve. Microencapsulation of various hydrophobic liquids is well known. Microcapsules have been suggested for encapsulation of perfumes, medicines, adhesives, dyestuffs, inks, etc.